This invention relates to novel foods for animals and to methods of making the same. More particularly, it relates to dried farinaceous and proteinaceous meaty products having a substantially higher palatibility than other coated products presently used in the trade. It also has a high nutritional and caloric value and may be used as a maintenance food, stored and marketed in nonrefrigerated containers without the need of hermetically sealed containers. The product can be provided in the form of small kibbles or, as preferred, in greater than bite-size, for example in the form of large, molded bone-shaped pieces. Particularly in the latter form, the product has a uniformly palatable taste throughout, that is, the biscuit is palatable when bitten into as well as when first taken into the pet's mouth. The products do not become mushy when served with liquid but retain their dry, solid characteristics and retain their meaty characteristic.
Dog and cat foods are commonly prepared as either meal-type rations or canned-type rations and are commonly formulated from a combination of proteinaceous and farinaceous materials. The proteinaceous material is derived from either vegetable protein sources or from meat and/or meat by-products, and nutritional supplements are often added. Meal-type animal foods have a dry, cereal-like texture and low moisture content, typically about 10%. They usually have a very high nutritional and caloric value providing a complete balanced diet for the animal, and excellent storage characteristics, thus permitting the use of relatively inexpensive packaging techniques. However, the palatability of many dry meal-type animal foods is poor and, in many cases, the animal will not eat them at all in dry form, necessitating the addition of liquids prior to their consumption. Liquid addition can cause the products to become mushy and on that basis could be rejected by the animal.
Canned-type animal foods having a meat-like texture and high-moisture content are generally received quite favorably by animals, apparently due in part to their meaty-texture, consistency and aroma. However, the elevated moisture content of such products requires thermal processing in sealed containers to obtain a commercially sterile product, thereby adding considerably to product costs. Furthermore, once such a can is opened, it must be quickly consumed since the product is quite conducive to supporting microbiological growth and hence will deteriorate very rapidly unless stored under refrigeration.
In addition to the two foregoing general types of animal foods, intermediate moisture products, having a moisture content in the range of about 15%-30%, have also been made available. In order to avoid microbiological decomposition, such products must be specially processed, e.g. by thorough pasturization, and/or by being packaged in hermetically sealed containers and commercially sterilized, or maintained in a frozen or refrigerated state. Another approach is to disperse an aqueous phase of water soluble solids uniformly throughout the product, the soluble solids being principally sugar at a level high enough to exert a bacteriostatic effect sufficient to stabilize the animal food. Such a product is illustrated by H. M. Burgess U.S. Pat. No. 3,202,514. The high sugar content of such products is not palatable to all animals, nor is it nutritionally sound.
Thus, there has not been provided an animal food product which has the high palatability associated with the meaty texture of canned food and the convenience and high nutritional value associated with meal-type foods. The present invention provides such products. In particular, there is provided a dried cereal based pet food composed of farinaceous and proteinaceous materials encapsulated within a glazed coating composed of liver and farinaceous material, the combination of which has a synergistic effect that excites the taste buds of the pet more than either of the highly palatable ingredients taken separately. In a preferred form, the matrix of farinaceous and proteinaceous material is formed to provide a core of desired shape and baked to less than 18% moisture by weight. While the shaped matrix is extremely hot, i.e. having an internal temperature in excess of 200.degree. F., the product is immersed in a meaty coating of farinaceous material and liver having a lower temperature, causing a sudden drop in temperature which creates a partial vacuum in the inner core of the shaped matrix, drawing the aroma and flavor of the coatng material into the matrix, which is then trapped within the core by a second baking that forms a hard crust of dried meaty substance on the exterior to encapsulate the matrix. More specifically, liver constitutes at least 50% of the coating formulation by weight, exclusive of water. Such a coating not only provides a meaty taste, but also enables formation of a hard, glazed crust, greatly enhancing the product's attractiveness to pets. The liver should be comminuted to form a slurry which can be maintained by the addition of vegetable enzymes as described hereafter.
In a further preferred embodiment, prior to baking the cores are formed from a combination of uncooked farinaceous material and meat by-product in a particular form. Specifically, the meat or meat by-product is uncooked and in the form of finely cut flakes. This is combined with the uncooked farinaceous material, such as wheat, and blended to form a pasty dough which is molded into discrete pieces. The pieces are then baked at a temperature sufficiently high, e.g. 350.degree.-650.degree. F. to provide dry, solid cores having a moisture content of less than 18% by weight. The baked cores are coated with the high liver content coating, as above, then subjected to a second baking step, again at a preferred temperature of about 350.degree.-650.degree. F., to reduce the moisture content, also to less than 18% by weight, preferably to a range between 8% and 18% by weight. The result is a product having high palatability throughout, and having a surface which does not become mushy when immersed in water or other liquid. The product is hard and solid, yet meaty in taste. With the simple addition to the core formulation of an antioxidant and an antimycotic agent, the product can be packaged using relatively inexpensive techniques and stored without spoilage.
It is particularly advantageous for the core to be formed of uncooked (that is other than as a result of the baking step) meat or meat by-product which is in the form of finely cut flakes, preferably having its largest dimension in the range of 15/1000 inch to 250/1000 inch. The flakes are blended with farinaceous material, such as wheat, serving as an adhesive to form a pasty dough, preferably without adding water. In addition, one can add a small amount of a source of edible oil, such as soy oil or soybeans, which not only adds protein but also serves to bring out the meaty flavor and helps with molded pieces in release of the product from the mold. One can also add other ingredients such as ground corn, for example in the form of flour, to add additional flavor and aroma to the biscuit. The following ranges of core ingredients, wherein percentages are by weight, are suitable.
______________________________________ Finely cut flakes of uncooked meat or meat by-product 5-25% Ground uncooked wheat 40-93% Ground corn 0-20% Source of edible oil, calculated as oil 2-15% ______________________________________
The components are blended to form a pasty dough. To obtain molded biscuits, the dough is fed into a pair of opposing plates defining cavities in the desired shape, such as bones, and then molded therein. The molded pieces are then baked under time and temperature conditions sufficient to form the desired dry, solid, molded product. For example, the pieces can be baked at a temperature of about 350.degree.-600.degree. F. for five minutes to an hour, conveniently in a continuous oven to reduce moisture content to less than 18% by weight, preferably to a range between 8% and 18%. The high temperature used in the baking step is particularly important to achieving a dry solid surface that resists mushing, whereas the prior art has found that palatability suffers when such high temperatures are used (e.g. Ludington et al U.s. Pat. No. 3,119,691). Products of the present inventions have a high degree of palatability perhaps as a result of combining such a high temperature in the baking step with the use of finely cut flakes of meat or meat by-product.
Critical to successful coating in accordance with the present invention is the use of a slurry of comminuted liver, preferably beef liver, in sufficient concentration, at least 50% by weight of the slurry, exclusive of moisture to provide a glazed, encapsulating coating when baked. Vegetable enzyme is preferably added to the coating formulation. Up to about 3% by weight is useful to keep the liver in a liquid state, prevent coagulation and keep it non-fibrous. The enzyme becomes active at 86.degree. F. and deteriorates at 122.degree. F. so that it is lost in baking. One can also add ground whole wheat which acts as a binder to hold the coating together. Various colors and flavoring can be added to simulate different meat flavors and appearances. Antioxidant and antimycotic agents can be added and sufficient water is added to achieve the desired viscosity.
Whether being applied to kibble-like pieces or to the preferred baked combination of uncooked farinaceous material and finely cut flakes of uncooked meat or meat by-product, the combination of high liver content and high temperature baking provides a glazed encapsulation presenting to the animal a highly attractive textural, olfactory and visual combination. Particularly, the preferred double baked product has high palatability throughout. Accordingly, large sized pieces can be provided, greater than bite-size (4 cm. long or larger) which can be bitten into by the animal without loss of palatability.